Unlocking Enhanced Capacitive Deionization of NaTi2(PO4)3/Carbon Materials by the Yolk-Shell Design.

The low salt adsorption capacities (SACs) of benchmark carbon materials (usually below 20 mg g-1) are one of the most challenging issues limiting further commercial development of capacitive deionization (CDI), an energetically favorable method for sustainable water desalination. Sodium superionic conductor (NASICON)-structured NaTi2(PO4)3 (NTP) materials, especially used in combination with carbon to prepare NTP/C materials, provide emerging options for higher CDI performance but face the problems of poor cycling stability and dissolution of active materials. In this study, we report the development of the yolk-shell nanoarchitecture of NASICON-structured NTP/C materials (denoted as ys-NTP@C) using a metal-organic framework@covalent organic polymer (MOF@COP) as a sacrificial template and space-confined nanoreactor. As expected, ys-NTP@C exhibits good CDI performance, including exemplary SACs with a maximum SAC of 124.72 mg g-1 at 1.8 V in the constant-voltage mode and 202.76 mg g-1 at 100 mA g-1 in the constant-current mode, and good cycling stability without obvious performance degradation or energy consumption increase over 100 cycles. Furthermore, X-ray diffraction used to study CDI cycling clearly exhibits the good structural stability of ys-NTP@C during repeated ion intercalation/deintercalation processes, and the finite element simulation shows why yolk-shell nanostructures exhibit better performance than other materials. This study provides a new synthetic paradigm for preparing yolk-shell structured materials from MOF@COP and highlights the potential use of yolk-shell nanoarchitectures for electrochemical desalination.

Deciphering an Abnormal Layered-Tunnel Heterostructure Induced by Chemical Substitution for the Sodium Oxide Cathode.

Demands for large-scale energy storage systems have driven the development of layered transition-metal oxide cathodes for room-temperature rechargeable sodium ion batteries (SIBs). Now, an abnormal layered-tunnel heterostructure Na0.44 Co0.1 Mn0.9 O2 cathode material induced by chemical element substitution is reported. By virtue of beneficial synergistic effects, this layered-tunnel electrode shows outstanding electrochemical performance in sodium half-cell system and excellent compatibility with hard carbon anode in sodium full-cell system. The underlying formation process, charge compensation mechanism, phase transition, and sodium-ion storage electrochemistry are clearly articulated and confirmed through combined analyses of in situ high-energy X-ray diffraction and ex situ X-ray absorption spectroscopy as well as operando X-ray diffraction. This crystal structure engineering regulation strategy offers a future outlook into advanced cathode materials for SIBs.

Evolution Path of Precursor-Induced High-Temperature Lithiation Reaction during the Synthesis of Lithium-Rich Cathode Materials.

High-temperature lithiation is one of the crucial steps for the synthesis of Li- and Mn-rich layered metal oxide (LMLO) cathodes. A profound insight of the micromorphology and crystal structure evolution during calcination helps to realize the finely controlled preparation of final cathodes, finally achieving a desired electrochemical performance. In this work, two typical precursors (hydroxide and oxalate) were selected to prepare LMLO. It is found that the influence of the lithium source on reaction pathways is determined by the properties of precursors. In the case of hydroxide as a precursor, whatever lithium sources it is, the flake morphology of LMLO is inherited from hydroxide precursors. This is because the crystal structure of cathode products has a high similarity with its precursor in terms of the oxygen array arrangement, and the topological transformation occurs from hydroxide (P-3ml) to LMLOs (C/2m and R3m). Thus, the morphology and microstructure of LMLO cathodes could be well controlled only by tuning the properties of hydroxide precursors. Conversely, the decomposition of a lithium source has a great influence on the intermediate transformation when oxalate is used as the precursor. This is because a large amount of CO2 is released from the oxalate precursor after the decomposition reaction, resulting in drastic structural changes. At this time, the diffusion ability of the lithium source leads to the competition between the spinel phase and layered phase. Based on this point, the formation of a spinel intermediate phase can be reduced by accelerating the decomposition of the lithium source, contributing to the generation of a highly pure layered phase, thus exhibiting higher electrochemical performance. These insights provide an exciting cue to the rational selection and design of raw materials and lithium sources for the controlled synthesis of LMLO cathodes.

Optimizing Vanadium Redox Reaction in Na3V2(PO4)3 Cathodes for Sodium-Ion Batteries by the Synergistic Effect of Additional Electrons from Heteroatoms.

Na3V2(PO4)3 (NVP) is one of the most potential cathode materials for sodium-ion batteries (SIBs), but its actual electrochemical performance is limited by the defects of large electron and ion transfer resistance. Multicomponent design is considered an effective method to optimize the conductivity of NVP electrodes. Therefore, Cr and Si are added in NVP to form a multielement component of Na3V1.9Cr0.1(PO4)2.9(SiO4)0.1 (NVP-CS). It is confirmed that 3d electrons of Cr are beneficial for improving the conductivity and increasing the average potential by activating V4+/V5+. Theoretical calculations show that the introduction of Si changes the electronic structure of V and O, thus promoting the electrochemical reaction of V3+/V4+ to exert higher capacity. Due to the coordination of the two elements, a lower migration barrier is obtained in NVP-CS. Specifically, NVP-CS retains the advantages of single-doped electrodes very well (capacity retention of 90% after 300 cycles at 1 C and a high capacity of 94.1 mA h g-1 at 5 C, compared to NVP with only 82.6% capacity retention at 1 C and 59.4 mA h g-1 at 5 C). The excellent electrochemical performance results show that NVP can be successfully optimized by the introduction of Cr and Si. This work can provide some inspiration for multicomponent material research of cathode materials.

Dual-Modified Compact Layer and Superficial Ti Doping for Reinforced Structural Integrity and Thermal Stability of Ni-Rich Cathodes.

Nickel-rich layered oxides have been regarded as a potential cathode material for high-energy-density lithium-ion batteries because of the high specific capacity and low cost. However, the rapid capacity fading due to interfacial side reactions and bulk structural degradation seriously encumbers its commercialization. Herein, a highly stable hybrid surface architecture, which integrates an outer coating layer of TiO2&Li2TiO3 and a surficial titanium doping by incorporated Ti2O3, is carefully designed to enhance the structural stability and eliminate lithium impurity. Meanwhile, the surficial titanium doping induces a nanoscale cation-mixing layer, which suppresses transition-metal-ion migration and ameliorates the reversibility of the H2 → H3 phase transition. Also, the Li2TiO3 coating layer with three-dimensional channels promotes ion transportation. Moreover, the electrochemically stable TiO2 coating layer restrains side reactions and reinforces interfacial stability. With the collaboration of titanium doping and TiO2&Li2TiO3 hybrid coating, the sample with 1 mol % modified achieves a capacity retention of 93.02% after 100 cycles with a voltage decay of only 0.03 V and up to 84.62% at a high voltage of 3.0-4.5 V. Furthermore, the ordered occupation of Ni ions in the Li layer boosts the thermal stability by procrastinating the layered-to-rock salt phase transition. This work provides a straightforward and economical modification strategy for boosting the structural and thermal stability of nickel-rich cathode materials.

New Insights into the Mechanism of Enhanced Performance of Li[Ni0.8Co0.1Mn0.1]O2 with a Polyacrylic Acid-Modified Binder.

A binder is an important component in lithium-ion batteries and plays a significant role in maintaining the properties of active substances. Most studies in the field of binders have only focussed on physical properties such as bonding performance. Here, a polyacrylic acid-modified binder was designed and adapted to Li[Ni0.8Co0.1Mn0.1]O2, which enhanced the electrochemical stability of Li[Ni0.8Co0.1Mn0.1]O2 from 30.2 to 66.6% (300 cycles at 1 C). We for the first time discovered that this was caused by a chemical reaction between polyacrylic acid and the residual lithium on the surface during the cycling, which formed a lithium propionic acid coating layer and maintained the stability of the layered structure.

Interfacial Regulation of Ni-Rich Cathode Materials with an Ion-Conductive and Pillaring Layer by Infusing Gradient Boron for Improved Cycle Stability.

Ni-rich cathodes LiNixCoyAl1-x-yO2 (0.8 < x < 1) with high energy density, environmental benignity, and low cost are regarded as the most promising candidate materials for next-generation lithium batteries. Unfortunately, capacity fading derived from unstable surface properties and intrinsic structural instability under extreme conditions limits large-scale commercial utilization. Herein, an interface-regulated Ni-rich cathode material LiNi0.87Co0.10Al0.03O2 with a layer (R3̅m) core, a NiO salt-like (Fm3̅m) phase, and an ultrathin amorphous ion-conductive LiBO2 (LBO) layer is constructed by gradient boron incorporation and lithium-reactive coating during calcination. The ultrathin LBO layer not only exhausts residual lithium species but also acts as a layer for Li+ transport and insulation of detrimental reaction. The NiO salt-like phase in the subsurface could enhance the structural stability of the layer core for the pillar effects. With the positive role provided by the functional hybrid surface layer and boron doping, the modified cathode exhibits enhanced Li+ conductivity, structural stability, reversibility of the H2-H3 phase transition, suppressed side reactions, ameliorated transition-metal dissolution, and excellent electrochemical performance. Especially, a 1% wt boron-modified cathode delivers a discharge capacity of 211.99 mA h g-1 in the potential range of 3.0-4.3 V at 0.2 C and excellent cycle life with a capacity retention of 89.43% after 200 cycles at 1 C.

Hydrangea-Like CuS with Irreversible Amorphization Transition for High-Performance Sodium-Ion Storage.

Metal sulfides have been intensively investigated for efficient sodium-ion storage due to their high capacity. However, the mechanisms behind the reaction pathways and phase transformation are still unclear. Moreover, the effects of designed nanostructure on the electrochemical behaviors are rarely reported. Herein, a hydrangea-like CuS microsphere is prepared via a facile synthetic method and displays significantly enhanced rate and cycle performance. Unlike the traditional intercalation and conversion reactions, an irreversible amorphization process is evidenced and elucidated with the help of in situ high-resolution synchrotron radiation diffraction analyses, and transmission electron microscopy. The oriented (006) crystal plane growth of the primary CuS nanosheets provide more channels and adsorption sites for Na ions intercalation and the resultant low overpotential is beneficial for the amorphous Cu-S cluster, which is consistent with the density functional theory calculation. This study can offer new insights into the correlation between the atomic-scale phase transformation and macro-scale nanostructure design and open a new principle for the electrode materials' design.

Dual Elements Coupling Effect Induced Modification from the Surface into the Bulk Lattice for Ni-Rich Cathodes with Suppressed Capacity and Voltage Decay.

Injection of phase transition from a layered to rock-salt phase into the bulk lattice and side reactions on the interfacial usually causes structure degradation, quick capacity/voltage decay, and even thermal instability. Here, a self-formed interfacial protective layer coupled with lattice tuning was constructed for Ni-rich cathodes by simultaneous incorporation of Zr and Al in a one-step calcination. The migration energy between Zr and Al from the surface into the bulk lattice induces dual modifications from the surface into the bulk lattice, which effectively decrease the formation of cation mixing, the degree of anisotropic lattice change, and the generation of microcracks. With the stabilization role provided by the doped Zr-Al ions and protective function endowed by the surface layer, the modified cathode material exhibits significantly enhanced capacity and voltage retention. Specifically, the capacity retention for the modified cathode material reaches 99% after 100 cycles at 1 C and 25 °C in a voltage range of 3.0-4.3 V, which outperformed that for the pristine cathode (70%). The declination values of the average voltage for the modified cathode are only 0.025 and 0.097 V after 100 cycles at 1 C in voltage ranges of 3.0-4.3 and 2.8-4.5 V, respectively, which are much lower than those for the pristine cathode (0.230 and 0.405 V). The synchronous accomplishment of modification from the surface into the bulk lattice for Ni-rich materials with multiple elements in a one-step calcination process would provide some referenced value for the preparation of other cathode materials.

Targeted inhibition of the EGFR pathways enhances Zn-BC-AM PDT-induced apoptosis in well-differentiated nasopharyngeal carcinoma cells.

Epidermal growth factor receptor (EGFR), a receptor often expressed in nasopharyngeal carcinoma (NPC) cells, is one of the recently identified molecular targets in cancer treatment. In the present study, the effects of combined treatment of Zn-BC-AM PDT with an EGFR inhibitor AG1478 were investigated. Well-differentiated NPC HK-1 cells were subjected to PDT with 1 microM of Zn-BC-AM and were irradiated at a light dose of 1 J/cm(2) in the presence or absence of EGFR inhibitor AG1478. Specific protein kinase inhibitors of downstream EGFR targets were also used in the investigation. EGFR, Akt, and ERK were found constitutively activated in HK-1 cells and the activities could be inhibited by the EGFR inhibitor AG1478. A sub-lethal concentration of AG1478 was found to further enhance the irreversible cell damage induced by Zn-BC-AM PDT in HK-1 cells. Pre-incubation of the cells with specific inhibitors of EGFR (AG1478), PI3k/Akt (LY294002), or MEK/ERK (PD98059) before light irradiation were found to enhance Zn-BC-AM PDT-induced formation of apoptotic cells. The efficacy of Zn-BC-AM PDT can be increased through the inhibition of EGFR/PI3K/Akt and EGFR/MEK/ERK signaling pathways in NPC cells. Combination therapy with Zn-BC-AM PDT and EGFR inhibitors may further be developed for the treatment of advanced NPC.

Ion-Doping-Site-Variation-Induced Composite Cathode Adjustment: A Case Study of Layer-Tunnel Na0.6MnO2 with Mg2+ Doping at Na/Mn Site.

Composite cathodes have attracted great attention due to the integrated advantages of each pure structure. Also, the component ratio deserves a careful modulation to further improve the corresponding electrochemical performance. Mn-based layer-tunnel hybrid composite became a focus in sodium-ion batteries due to the superiority in terms of high performance, low cost, and nontoxicity. In the previous reports, the structure modulation was carried out via changing the synthesis condition, varying the transition-metal-element ratio, and different ion doping. Also, it is still challenging to explore a more feasible method to simplify the adjustment process. Herein, we introduced Mg2+ into Na sites or transition-metal sites in Na0.6MnO2 and first discovered the doping-site-variation-induced structural adjustment phenomenon. Specifically, Mg doping in transition-metal sites could be beneficial for the growth of the P2-type structure, while layer/tunnel component ratio decreased when locating Mg2+ in Na sites. The P2-O2 phase transformations could be effectively suppressed by locating Mg2+ in both sites in high-voltage regions and thus improve the cycling performance. The designed material, Na0.6Mn0.99Mg0.01O2, could attain a decent capacity of 100 mA h g-1 at 1000 mA g-1 and a satisfied retention of 76.6% after 500 cycles. Additionally, ex situ X-ray diffraction analysis experiments verify the excellent structural stability of Mg-substituted samples during charge-discharge processes. Moreover, the Na0.6Mn0.99Mg0.01O2 also displays superior sodium-ion full-cell properties when merged with hard carbon anode. Thus, this research may indicate a proper novel thread for designing high-performance composite electrodes.

Revealing of the Activation Pathway and Cathode Electrolyte Interphase Evolution of Li-Rich 0.5Li2MnO3·0.5LiNi0.3Co0.3Mn0.4O2 Cathode by in Situ Electrochemical Quartz Crystal Microbalance.

The first-cycle behavior of layered Li-rich oxides, including Li2MnO3 activation and cathode electrolyte interphase (CEI) formation, significantly influences their electrochemical performance. However, the Li2MnO3 activation pathway and the CEI formation process are still controversial. Here, the first-cycle properties of xLi2MnO3·(1- x) LiNi0.3Co0.3Mn0.4O2 ( x = 0, 0.5, 1) cathode materials were studied with an in situ electrochemical quartz crystal microbalance (EQCM). The results demonstrate that a synergistic effect between the layered Li2MnO3 and LiNi0.3Co0.3Mn0.4O2 structures can significantly affect the activation pathway of Li1.2Ni0.12Co0.12Mn0.56O2, leading to an extra-high capacity. It is demonstrated that Li2MnO3 activation in Li-rich materials is dominated by electrochemical decomposition (oxygen redox), which is different from the activation process of pure Li2MnO3 governed by chemical decomposition (Li2O evolution). CEI evolution is closely related to Li+ extraction/insertion. The valence state variation of the metal ions (Ni, Co, Mn) in Li-rich materials can promote CEI formation. This study is of significance for understanding and designing Li-rich cathode-based batteries.

Treatment of osteonecrosis of femoral head with BMSCs-seeded bio-derived bone materials combined with rhBMP-2 in rabbits.

OBJECTIVE: To evaluate the effect of autologous bone marrow mesenchymal stem cells (BMSCs) seeded bio-derived bone materials (BBM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) in repairing defect of osteonecrosis of femoral head (ONFH). METHODS: Early-stage osteonecrosis in the left hip was induced in 36 adult New Zealand white rabbits (provided by the Animal Center of Guangxi Medical University, Nanning, China) after core decompression and delivery of liquid nitrogen into the femoral head. Then the animals were divided into three groups according to the type of implants for bone repair: 12 rabbits with nothing (Group I, the blank control group), 12 with BBM combined with rhBMP-2 (Group II), and 12 with BMSCs-seeded BBM combined with rhBMP-2 (Group III). At 4, 8, and 12 weeks after surgery, X-ray of the femoral head of every 4 rabbits in each group was taken, and then they were killed and the femoral heads were collected at each time point, respectively. Gross observation was made on the femoral heads. After hematoxylin and eosin staining, Lane-sandhu scores of X-ray and bone densitometry were calculated and the histomorphometric measurements were made for the new bone trabeculae. RESULTS: At 12 weeks after surgery, two femoral heads collapsed in Group I, but none in Group II or Group III. X-ray examination showed that the femoral heads in Group I had defect shadow or collapsed while those in Group II had a low density and those in Group III presented with a normal density. Histologically, the defects of femoral heads were primarily filled with no new bone but fibrous tissues in Group I. In contrast, new bone regeneration and fibrous tissues occurred in Group II and only new bone regeneration occurrd in Group III. Lane-sandhu scores of X-ray, bone mineral density and rate of new bone in trabecular area in Group III were higher significantly than those of the other two groups. CONCLUSIONS: Our findings indicate a superior choice of repairing the experimental defect of ONFH with BMSCs- seeded BBM combined with rhBMP-2.

Three-Dimensional Chestnut-Like Architecture Assembled from NaTi3O6(OH)·2H2O@N-Doped Carbon Nanosheets with Enhanced Sodium Storage Properties.

The application of sodium titanate anodes of low cost, feasible operating voltage, and nontoxic nature were severely hindered by their inferior cycling stability and poor rate capability. Here, three-dimensional (3D) chestnut-like NaTi3O6(OH)·2H2O@N-doped carbon nanospheres (NTOH@CN) with loose crystal structures were prepared by a self-sacrificed template method. The nanospheres were composed of nanosheets and linked with nanowires, which interweaved to construct a meshwork structure. The growth mechanism of unique 3D NTOH@CN nanospheres was investigated by tracking the synthesis process of different hydrothermal durations. The rate performances of 3D NTOH@CN were superior to that of NaTi3O6(OH)·2H2O irregular spheres assembled from nanosheets (3D NTOH) and NaTi3O6(OH)·2H2O nanosheets (two-dimensional NTOH). Excellent cycling and rate performance were obtained due to their open crystal structure, unique 3D nanosphere morphology with short diffusion paths, N-doped carbon surrounding, and the solid solution reaction. In addition, the reaction mechanism, morphology change, and dynamics research during the sodium insertion/desertion process have been carefully studied. Based on varying ex situ analyses, the irreversible metallic titanium formation and the excellent structural stability of nanosphere morphology have been evidenced. The pseudocapacitive phenomenon was also detected, which effectively enhanced Na+ ion storage capability. The systematical and comprehensive study provide a holograph for the design and synthesis of sodium titanate nanostructures.

Constructing a Protective Pillaring Layer by Incorporating Gradient Mn4+ to Stabilize the Surface/Interfacial Structure of LiNi0.815Co0.15Al0.035O2 Cathode.

Nickel-rich layered oxides are regarded as very promising materials as cathodes for lithium-ion batteries because of their environmental benignancy, low cost, and high energy density. However, insufficient cycle performance and poor thermotic characteristics induced by structural degradation at high potentials and elevated temperatures pose challenging hurdles for nickel-rich cathodes. Here, a protective pillaring layer, in which partial Ni2+ ions occupy Li slabs induced by gradient Mn4+, is integrated into the primary particle of LiNi0.815Co0.15Al0.035O2 to stabilize the surface/interfacial structure. With the stable outer surface provided by the enriched Mn4+ gradient concentration and the pillar effect of the NiO-like phase, Mn-incorporated quaternary cathodes show enhanced structural stability and improved Li+ diffusion as well as lithium-storage properties. Compared with the severe capacity fade of a pure layered structure, the cathode with gradient Mn4+ exhibits more stable cycling behavior with a capacity retention of 80.0% after 500 cycles at 5.0 C.

Cu2+ Dual-Doped Layer-Tunnel Hybrid Na0.6Mn1- xCu xO2 as a Cathode of Sodium-Ion Battery with Enhanced Structure Stability, Electrochemical Property, and Air Stability.

Sodium-ion batteries (SIBs) have been regarded as a promising candidate for large-scale renewable energy storage system. Layered manganese oxide cathode possesses the advantages of high energy density, low cost and natural abundance while suffering from limited cycling life and poor rate capacity. To overcome these weaknesses, layer-tunnel hybrid material was developed and served as the cathode of SIB, which integrated high capacity, superior cycle ability, and rate performance. In the current work, the doping of copper was adopted to suppress the Jahn-Teller effect of Mn3+ and to affect relevant structural parameters. Multifunctions of the Cu2+ doping were carefully investigated. It was found that the structure component ratio is varied with the Cu2+ doping amount. Results demonstrated that Na+/vacancy rearrangement and phase transitions were suppressed during cycling without sacrificing the reversible capacity and enhanced electrochemical performances evidenced with 96 mA h g-1 retained after 250 cycles at 4 C and 85 mA h g-1 at 8 C. Furthermore, ex situ X-ray diffraction has demonstrated high reversibility of the Na0.6Mn0.9Cu0.1O2 cathode during Na+ extraction/insertion processes and superior air stability that results in better storage properties. This study reveals that the Cu2+ doping could be an effective strategy to tune the properties and related performances of Mn-based layer-tunnel hybrid cathode.

Insight into the Origin of Capacity Fluctuation of Na2Ti6O13 Anode in Sodium Ion Batteries.

The capacity fluctuation phenomenon during cycling, which is closely related with solid electrolyte interphase and plays a key role for the design for advanced electrode, could be frequently observed in the titanium-based anode. However, the underlying reason for capacity fluctuation still remains unclear with rare related reports. Here, the origin of capacity fluctuation is verified with a long-life Na2Ti6O13 anode. The reaction mechanism, structural evolution and reaction kinetics during the reported sodiation/desodiation processes were carefully investigated. The gradually enhanced diffusion controlled contribution resulted in the capacity increasing. And the capacity decay could be ascribed to the irreversible reaction of metallic titanium formation and the increasing potential polarization. It is worth noting that sodium ions seem to partially reduce NTO to metallic state, which is irreversible. The present study can provide more information for the design of advanced Na2Ti6O13 anode.

Layered/Spinel Heterostructured and Hierarchical Micro/Nanostructured Li-Rich Cathode Materials with Enhanced Electrochemical Properties for Li-Ion Batteries.

Although holding a high capacity, Li-rich materials are far from the demand of practical market because of their inherent drawbacks, such as poor initial efficiency and rate capability. Herein, Li-rich materials of Li1.16Mn0.6Ni0.12Co0.12O2 have been prepared via a one-step solvothermal strategy. The detail characterizations demonstrate that the as-prepared materials present morphology of nanoparticle-aggregated hierarchical microspheres and a heterostructure of layered and Li4Mn5O12-type spinel components. Compared to materials of pure-layered structure, layered/spinel heterostructured materials exhibit simultaneously great reversible capacity (302 mAh g-1 at 0.2 C), high initial Coulombic efficiency (94% at 0.2 C) and remarkable rate capability (193 mAh g-1 at 10 C).

Mn-Based Cathode with Synergetic Layered-Tunnel Hybrid Structures and Their Enhanced Electrochemical Performance in Sodium Ion Batteries.

A synergistic approach for advanced cathode materials is proposed. Sodium manganese oxide with a layered-tunnel hybrid structure was designed, synthesized, and subsequently investigated. The layered-tunnel hybrid structure provides fast Na ion diffusivity and high structural stability thanks to the tunnel phase, enabling high rate capability and greatly improved cycling stability compared to that of the pure P2 layered phase while retaining the high specific capacity of the P2 layered phase. The hybrid structure provided a decent discharge capacity of 133.4 mAh g-1 even at 8 C, which exceeds the reported best rate capability for Mn-based cathodes. It also displayed an impressive cycling stability, maintaining 83.3 mAh g-1 after 700 cycles at 10 C. Theoretical calculation and the potentiostatic intermittent titration technique (PITT) demonstrated that this hybrid structure helps enhance Na ion diffusivity during charge and discharge, attaining, as a result, an unprecendented electrochemical performance.

Suppressing the voltage-fading of layered lithium-rich cathode materials via an aqueous binder for Li-ion batteries.

Guar gum (GG) has been applied as a binder for layered lithium-rich cathode materials of Li-ion batteries for the first time. Compared with the conventional PVDF binder, electrodes with GG as the binder exhibit significantly suppressed voltage and capacity fading. This study has introduced a multi-functional binder for layered lithium-rich cathode materials.